CHICAGO (AP) — Mayor Rahm Emanuel is urging mayors nationwide to follow Chicago's lead and sever ties with companies that make or sell assault weapons.

Emanuel says mayors have first-hand knowledge of the damage the weapons cause. He told a meeting of the U.S. Conference of Mayors on Saturday that there's no return on investment great enough to justify support for the companies.

Last week, Emanuel ordered a portfolio analysis of five pension and retirement funds for Chicago employees to determine if they include investments in gun makers. He has asked the Chicago Transit Authority, Chicago Housing Authority and the park district to do the same.